dsh-sm-context-piano

Long-running agent sessions can accumulate hundreds of messages where tool calls, edit records, reasoning traces, and user instructions are all tangled together. A traditional scrollbar only tells you "you are at pixel 837" but never tells you "this is where the model revised the auth module for the third time." sm-context-piano renders a compact set of horizontal piano keys along the left edge of the chat pane, compressing the conversation into browsable, positionable semantic nodes. Hover to read a summary, click or press Enter to jump straight to the target paragraph, and stop fighting the scroll bar every time you need context.

The keys only represent user messages and visible model text. Tool calls, edits, reads, reasoning, and internal state never create a key; they merely act as boundaries that split model output into independent segments. Consecutive model text is merged into a single key, while output from different phases stays separate. When the node count exceeds the limit, a fixed window centred on your current reading position is shown, and selecting the top or bottom key pages you to earlier or later content. During streaming, existing key DOM nodes are reused incrementally so the track never flickers or rebuilds from scratch.

This plugin is for anyone working in the DeepSeek Harness Web GUI with long conversations, multi-turn agent tasks, or code-collaboration sessions. It does not alter session content, trim model context, inject system prompts, or send any network requests. Hover previews are written as plain text, and a full unload removes every DOM node, listener, observer, and timer it created, leaving no residual side effects on the page.